The name Tony Iommi is synonymous with Black Sabbath -- as it should be. He’s the only member who has played on each of the band’s 18 studio albums (19 if you count Heaven & Hell).

One of those albums, 1982’s Born Again, recorded after the first departure of second vocalist Ronnie James Dio, was especially uncharacteristic. The disc featured Deep Purple singer Ian Gillan, and since it was a departure from traditional Sabbath vocally, the album was unfairly panned by critics.

A quick tour later, Gillan was gone and Black Sabbath were working with Glenn Hughes, then Tony Martin. But Iommi never dismissed his collaboration with Gillan and yearned for more. An opportunity presented itself in 1990, when he played guitar on the Deep Purple track “Smoke on the Water” a highlight of the benefit album Rock Aid Armenia: The Earthquake Album.

Another 20-plus years would pass before Iommi would have the chance to record with Gillan again for the recently released two-song Armenia benefit EP, Who Cares, which features the first original compositions between the two since Born Again.

Guitar World talked to Iommi about the two new songs, the other superstar guests on the EP, the final days with Dio and the guitarist’s upcoming biography, "Iron Man."

GUITAR WORLD: When did you write the songs for Who Cares?

It started eight months ago. I wrote the riff for the song “Out of My Mind” and Ian wrote “Holy Water.” Then [Iron Maiden drummer] Nicko [McBrain] flew into London to track the drums, and a few days later Ian and everyone else [bassist Jason Newsted, keyboardist Jon Lord and guitarist Linde Lindstrom] came to my home studio, Tone Hall, to record.

You previously played with Ian, of course. Did you work with Jon Lord as well, and was it fun to trade off guitar solos with keyboard runs?

I’ve always loved Jon Lord’s playing and his sound, but I’d never actually played with him before. So it was a great honor to be playing along with his keyboards.

When you wrote the song “Out of My Mind,” did you purposefully construct guitar parts that would compliment Ian’s voice and style?

I had the main riff and I played it for him and he said, “Oh, I like that.” And then we built the rest of the song together. Yes, you do cater for who’s going to be singing, but it flowed so naturally, it wasn’t difficult at all.

Did you use different gear or change the tone of your guitar when you played on these tracks?

No, I just used the amp I had in a studio, which was my Eddie Van Halen head. And then I plugged the old SG, and there you have it.

There’s less distortion on “Holy Water” than there is in Black Sabbath or Heaven and Hell.

“Yeah, we backed it off on 'Holy Water' to go along more with that Deep Purple sound.

Did you ever consider approaching Geezer Butler to play bass?

No, I was thinking we’d do something different because otherwise people would think we were getting Sabbath back together with Ian.

When did you first meet Jason Newsted, who plays bass on the EP?

Back when he joined Metallica. I always liked him and he was really up for it. We talked about doing a couple of shows together. He’s really good, and obviously, he’s a different sort of player than Geezer.

How did HIM guitarist Linde Lindstrom wind up on the project?

Well, my daughter [Toni-Marie Iommi] is engaged to him. He’s a good lad and I like him. When they were staying at the house, I said to Linde, “Do you fancy playing on this track we’re doing for charity?” And he was right into it.

A little more than a year has passed since the death of Ronnie James Dio. Of course, that was a huge tragedy, but at the same time you must feel good that you were able to put aside any differences you had from the past and record a final album with him, The Devil You Know.

It was great doing an album with Ronnie just a couple years ago that was really well regarded. Of course, that was a big, sad thing for us because we had finally got back together and we were really enjoying it, and, of course, Ronnie got ill. That was a great period, and we were talking about doing another album and certainly more touring. The tours were being put in right before he passed away. I spoke to Ronnie and it seemed like he was getting better. I said to him, “God, I can’t believe we’re going to be touring again.” And he said, “Well, you know, we’ll see.” And when he said that I thought, “Ohhhh.” But I didn’t realize how short this was going to be.

Your biography, “Iron Man: My Journey Through Heaven and Hell with Black Sabbath,” comes out November 1. How did that come together?

I had a chap called TJ Lammers, who I met many, many years ago when he used to work at Phonogram Records. He later became a journalist and he had his own magazine. He lives in Holland and we’ve stayed in touch over the years. I’ve had a few people say, “Oh, I can write a book for you,” but I wanted a different outlook to the normal music journalist, and that’s what happened. He came over to England and stayed with me for a few days. Then he’d write it up, come back again and do more. The whole thing took a couple years to finish.

How will this be different than the typical rock biography?

I don’t know. I don’t read rock biographies, so it could be the same, it could be different. It’s just my life, really. It’s about what happened and what I grew up from, and how I’ve gone through life to where I am now. It’s something I probably should have done a long time ago because there are so many books out now. I’ve been meaning to do it for many, many years but never got around to it.